Built, Not Bought: Replacing an Aging A.I.R. Flow Test Stand

For years, my A.I.R. Flow Test Stand did exactly what I needed it to do. It gave me a way to measure regulator performance with more than isolated gauge readings. It let me capture flow, vacuum, intermediate pressure, and tank pressure together, as a test event, and preserve that record for later review.

That mattered then, and it still matters now.

The problem is that the platform around it has aged out. The original system was built around Windows XP, Excel 2003, USB drivers, and legacy software architecture that is now increasingly difficult to keep alive through operating system changes and hardware turnover. The stand itself was a thoughtful design for its time, with multi-sensor capture, Excel-based logging, and a roughly 30 ms acquisition scan rate, but it has been out of production for well over a decade and is no longer a practical foundation for a modern service workflow.

I looked for a modern replacement. What I found was that most available shop systems still treat measurements as separate checks rather than a synchronized digital history. They can tell you a pressure. They can tell you a peak. But they often do not capture the full story across multiple sensors at once, and that limits both diagnostics and documentation.

I also considered adapting a high-end industrial acquisition platform. That could have worked technically, but it would have been expensive, cumbersome, and badly mismatched to the realities of a scuba service bench.

So I did what small specialist shops often end up doing when the industry does not build the right tool: I built one, with help from a friend.

The result is not just a replacement for an obsolete test stand. It is a better service system. It combines modern sensors, digital capture, workflow integration, and reporting in a way that reduces shop overhead while improving what the customer actually receives: better diagnostics, better records, and better confidence in the result. The new system is also integrated with SGS’s work order system, so test data stays tied to the specific equipment, the services performed, and the final reporting delivered to the customer. That gives the measurements operational context, linking performance results to what was serviced rather than treating them as standalone bench data.

That was the real goal from the start. Not to build a gadget. To build a better service process.

For the Geeks

The new bench is built around synchronized digital capture, not a pile of independent gauges. Vacuum is measured with a Honeywell HSCDRRN005NDAA5. Flow is calculated from differential pressure using a Honeywell HSCDRRN010NDAA5. Tank pressure is read through a DataQ 5000 psi high-precision pressure sensor, and intermediate pressure through a DataQ 300 psi high-precision pressure sensor.

An Arduino handles acquisition and feeds the software that plots, records, and manages the tests. That lets the system capture vacuum, flow, intermediate pressure, and tank pressure together as one time-based event instead of a series of isolated readings.

That matters because regulators are dynamic systems. Peaks alone do not tell the whole story. Time-correlated data does.